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authorLinas Vepstas <linas@austin.ibm.com>2006-10-30 16:15:59 +1100
committerPaul Mackerras <paulus@samba.org>2006-11-01 14:52:48 +1100
commit5d2efba64b231a1733c4048d1708d77e07f26426 (patch)
tree2893dd45b9c26cef6cddb5fef0c6f820c5eb534e /arch/powerpc/sysdev/dart_iommu.c
parentdd6c89f686bdb2a5de72fab636fc839e5a0add6d (diff)
[POWERPC] Use 4kB iommu pages even on 64kB-page systems
The 10Gigabit ethernet device drivers appear to be able to chew up all 256MB of TCE mappings on pSeries systems, as evidenced by numerous error messages: iommu_alloc failed, tbl c0000000010d5c48 vaddr c0000000d875eff0 npages 1 Some experimentation indicates that this is essentially because one 1500 byte ethernet MTU gets mapped as a 64K DMA region when the large 64K pages are enabled. Thus, it doesn't take much to exhaust all of the available DMA mappings for a high-speed card. This patch changes the iommu allocator to work with its own unique, distinct page size. Although the patch is long, its actually quite simple: it just #defines a distinct IOMMU_PAGE_SIZE and then uses this in all the places that matter. As a side effect, it also dramatically improves network performance on platforms with H-calls on iommu translation inserts/removes (since we no longer call it 16 times for a 1500 bytes packet when the iommu HW is still 4k). In the future, we might want to make the IOMMU_PAGE_SIZE a variable in the iommu_table instance, thus allowing support for different HW page sizes in the iommu itself. Signed-off-by: Linas Vepstas <linas@austin.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Acked-by: Olof Johansson <olof@lixom.net> Acked-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Paul Mackerras <paulus@samba.org>
Diffstat (limited to 'arch/powerpc/sysdev/dart_iommu.c')
-rw-r--r--arch/powerpc/sysdev/dart_iommu.c8
1 files changed, 1 insertions, 7 deletions
diff --git a/arch/powerpc/sysdev/dart_iommu.c b/arch/powerpc/sysdev/dart_iommu.c
index 03b4477dd7f0..572b7846cc77 100644
--- a/arch/powerpc/sysdev/dart_iommu.c
+++ b/arch/powerpc/sysdev/dart_iommu.c
@@ -156,9 +156,6 @@ static void dart_build(struct iommu_table *tbl, long index,
DBG("dart: build at: %lx, %lx, addr: %x\n", index, npages, uaddr);
- index <<= DART_PAGE_FACTOR;
- npages <<= DART_PAGE_FACTOR;
-
dp = ((unsigned int*)tbl->it_base) + index;
/* On U3, all memory is contigous, so we can move this
@@ -199,9 +196,6 @@ static void dart_free(struct iommu_table *tbl, long index, long npages)
DBG("dart: free at: %lx, %lx\n", index, npages);
- index <<= DART_PAGE_FACTOR;
- npages <<= DART_PAGE_FACTOR;
-
dp = ((unsigned int *)tbl->it_base) + index;
while (npages--)
@@ -281,7 +275,7 @@ static void iommu_table_dart_setup(void)
iommu_table_dart.it_busno = 0;
iommu_table_dart.it_offset = 0;
/* it_size is in number of entries */
- iommu_table_dart.it_size = (dart_tablesize / sizeof(u32)) >> DART_PAGE_FACTOR;
+ iommu_table_dart.it_size = dart_tablesize / sizeof(u32);
/* Initialize the common IOMMU code */
iommu_table_dart.it_base = (unsigned long)dart_vbase;